private Curve CreateSpiral(Plane plane, double r0, double r1, Int32 turns)
{
Line l0 = new Line(plane.Origin + r0 * plane.XAxis, plane.Origin + r1 * plane.XAxis);
Line l1 = new Line(plane.Origin - r0 * plane.XAxis, plane.Origin - r1 * plane.XAxis);
Point3d[] p0;
Point3d[] p1;
l0.ToNurbsCurve().DivideByCount(turns, true, out p0);
l1.ToNurbsCurve().DivideByCount(turns, true, out p1);
PolyCurve spiral = new PolyCurve();
for (int i = 0; i < p0.Length - 1; i++)
{
Arc arc0 = new Arc(p0[i], plane.YAxis, p1[i + 1]);
Arc arc1 = new Arc(p1[i + 1], -plane.YAxis, p0[i + 1]);
spiral.Append(arc0);
spiral.Append(arc1);
}
return spiral;
}
